JP2011080794A - Pulse radar device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive pulse radar device that can measure both of short-distance and long-distance target objects quickly with an improved S/N ratio by single pulse transmission and dispenses with increasing the dynamic range of an A/D converter even if there is an unnecessary connection within a circuit. <P>SOLUTION: Operation is performed to break a reception signal while transmitting pulse waves to the target objects by one type of transmission pulse width. As a result, for a reflection signal from the short-distance target object, pulses are partially removed by breaking operation of the reception signal and the pulse width becomes short, while a high S/N ratio is maintained by changing the bandwidth of a filter for the decrease in the pulse width. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pulse radar device that measures a distance to a target object and the like.

As a conventional pulse radar device, for example, there is one using a technique as shown in Patent Document 1 below.
FIG. 7 shows a configuration example of a conventional radar using a technique as described in Embodiment 2 (FIG. 4) of Patent Document 1.
The operation of the conventional radar will be described with reference to FIG.
A continuous wave is output from the oscillator 15, and the continuous wave is distributed to the transmission switch 5 and the mixer 6 by the distributor 4. In the transmission switch 5, as shown in FIG. 8, the continuous wave is divided into pulses based on an instruction from the CPU 1.

In FIG. 8, a pulse A is a pulse having a short pulse width for performing high-resolution measurement at a short distance. The pulse B is a pulse having a long pulse width for measuring a long distance.
The pulse signal generated in this way is radiated to a target object (not shown) as a radio wave via the transmission antenna 7, and the signal reflected by the target object is received by the reception antenna 8.
The signal received by the receiving antenna 8 is mixed with the continuous wave distributed by the distributor 4 by the mixer 6 to output a baseband signal having a band from DC to high frequency.

Here, since the bandwidth of the pulse signal is inversely proportional to the pulse width, a filter having a large bandwidth is used when receiving a pulse A having a short pulse width, and a bandwidth is small when receiving a pulse B having a long pulse width. By using the filter, the degradation of the SN ratio is suppressed.
More specifically, the low-pass filter 1 (LPF1) 11 or the low-pass filter set by the filter change-over switch 13 operates based on an instruction from the CPU 1 and is set to an appropriate bandwidth according to the received pulse width. 2 (LPF2) 12 is selected.
The baseband signal output from the mixer 6 passes through an appropriate low-pass filter (LPF) according to the pulse width, and is then sampled by the AD converter (ADC) 9 based on an instruction from the CPU 1. The distance to is calculated.
The received baseband signal has a pulse waveform with a delay time (2R / c (speed of light)) corresponding to the distance R to the target object with respect to the transmitted pulse.
Therefore, if the time difference between the transmission pulse and the reception pulse on the baseband signal is obtained, the distance to the target object can be calculated.

In such a conventional pulse radar device, it is necessary to transmit a pulse A for measuring a short distance and a pulse B for measuring a long distance in a time division manner.
For this reason, there is a problem in that it is impossible to measure the distance to the target object at both the short distance and the long distance by one pulse transmission, and it takes time for the measurement.

Further, due to unnecessary coupling in the circuit, the pulse signal generated by the transmission switch 5 is directly input to the mixer 6 and is detected as a signal larger than the reflected signal from the target object received by the receiving antenna 8.
For example, when it is assumed that the target object is an automobile, the reflected signal from the target object (automobile) having a radar cross section of 10 m ² existing at a close distance (1 m) with a carrier frequency of 76.5 GHz (wavelength 3.92 mm). Estimate the strength.
Here, if it is assumed that the antenna gains of the transmission antenna 7 and the reception antenna 8 are both 20 dB, they are calculated as shown in Equation (1) using the radar equation shown in the following Non-Patent Document 1 or the like. . Here, Pt is the power output from the transmission switch 5, and Pr is the power input to the mixer 6.

On the other hand, the pulse signal generated by the transmission switch 5 due to unnecessary coupling is directly input to the mixer 6 is generally about −20 dB, and the reflected signal from the target object at a close distance is, for example, an expression As shown in (1), it is about -31 dB.
Therefore, a signal in which the pulse signal generated by the transmission switch 5 due to unnecessary coupling is directly input to the mixer 6 is larger than the reflected signal from the target object at a close distance.
In order to be able to detect a small received signal from a target object at a long distance without being saturated by the AD converter 9 or the like even when a large unnecessary signal due to such unnecessary coupling is input, for example, the AD converter 9 Therefore, there is a problem that the dynamic range of the apparatus must be increased unnecessarily, resulting in an increase in the cost of the apparatus.

JP 2006-226847 A

Radar technology (p3-p4, p185) The Institute of Electronics, Information and Communication Engineers published in 1984

  The present invention has been made in order to solve the problems of the conventional apparatus as described above, and the distance to both the near and far target objects can be obtained in a short time by transmitting the pulse once. An object of the present invention is to provide a “low-cost pulse radar device” that can measure with a good S / N ratio and does not need to increase the dynamic range of the AD converter even if there is unnecessary coupling in the circuit.

  The pulse radar device according to the present invention includes an oscillating unit that oscillates and outputs a first continuous wave signal in a radio frequency band, and a second continuous signal that is phase-synchronized with the first continuous wave signal output by the oscillating unit. A second continuous wave signal generating means for generating a wave signal, a pulse modulating means for dividing the first continuous wave signal output from the oscillating means into a pulse wave, and outputting from the pulse modulating means Transmitting means for transmitting the pulse wave toward the target object, receiving means for receiving the pulse wave reflected by the target object, received signal received by the receiving means, and second continuous wave signal generation Mixing means for mixing the continuous wave signal generated by the means and outputting a mixed signal; and receiving switch means for preventing the mixed signal from being output from the mixing means while the pulse wave is being transmitted; The filter means for shaping the output signal from the receiving switch means, and the output signal from the filter means at a predetermined sampling interval with the time at which the first continuous wave signal is divided into pulses by the pulse modulation means as a reference time Sampling means for sampling and filter control means for changing the pass bandwidth of the filter means in accordance with the elapsed time from the reference time.

  The pulse radar device according to the present invention generates an oscillating means for oscillating and outputting a first continuous wave signal in a radio frequency band, and generates a pulse wave by dividing the continuous wave signal outputted from the oscillating means into pulses. When the pulse width of the generated pulse wave is a predetermined pulse width, the first pulse wave is generated by connecting to the transmission side, and when the pulse width of the generated pulse wave is other than the predetermined pulse width, reception is performed. Transmission / reception switching means for generating a second pulse wave by switching to the side, transmission means for transmitting the first pulse wave output from the transmission / reception switching means toward the target object, and the reflection reflected by the target object Receiving means for receiving the first pulse wave; mixing means for mixing the reception signal received by the receiving means and the second pulse wave output from the transmission / reception switching means; and outputting a mixed signal; and the receiving The Filter means for shaping the output signal from the switch means, sampling means for sampling the output signal from the filter means at a predetermined sampling interval with the time when the transmission / reception switching means is connected to the transmission side as a reference time, and the reference Filter control means for changing the pass bandwidth of the filter means according to the elapsed time from the time is provided.

According to the present invention, the distance to both near and far target objects can be measured in a short time and with a good SN ratio by one pulse transmission.
In addition, even if there is unnecessary coupling in the circuit, it is possible to avoid the saturation of the AD converter by removing the signal due to unnecessary coupling of the transmission pulse, so that it is not necessary to increase the dynamic range of the AD converter, and the cost of the apparatus can be reduced. .

It is a figure which shows the structure of the pulse radar apparatus by Embodiment 1 of this invention. 6 is a diagram illustrating a relationship between a frequency modulation signal and a transmission pulse signal in Embodiment 1. FIG. In Embodiment 1, it is a figure showing the relationship between a transmission signal and a received signal. In Embodiment 1, it is a figure showing the relationship between a transmission pulse, filter switching, and a sampling timing. It is a figure which shows the structure of the pulse radar apparatus by Embodiment 2 of this invention. In Embodiment 2, it is a figure showing the relationship between a transmission pulse, filter switching, and a sampling timing. It is a figure which shows the structural example of the conventional pulse radar apparatus. It is a figure showing the mode of the transmission pulse in the conventional pulse radar apparatus.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a pulse radar device according to Embodiment 1 of the present invention.
FIG. 2 is a diagram illustrating the relationship between the frequency modulation signal and the transmission pulse signal.
As shown in FIG. 1, the pulse radar device according to this embodiment outputs a modulation signal having a triangular waveform as shown in FIG. 2A from the modulation signal generator (FM) 2 based on an instruction from the CPU 1, The voltage is supplied to a VCO (Voltage Controlled Oscillator) 3.

In FIG. 2A, Tm represents a modulation time, and Fm represents a frequency modulation width.
A continuous wave (first continuous wave signal) frequency-modulated as shown in FIG. 2A is output from the VCO (voltage controlled oscillator) 3, and this continuous wave (first continuous wave signal) is output from the distributor 4. Is distributed to the transmission switch 5 and the mixer 6.
Needless to say, since the distributor 4 distributes and outputs the input signal (ie, the first continuous wave signal), the signal distributed and output by the distributor 4 (ie, the second continuous wave signal) is The phase is synchronized with the input signal (first continuous wave signal), and it becomes possible to output a baseband signal having a band from direct current to high frequency by mixing in the mixer 6 described later.

In the transmission switch 5, as shown in FIG. 2B, the continuous wave (first continuous wave signal) output from the VCO (voltage controlled oscillator) 3 is divided into pulses based on an instruction from the CPU 1. At this time, the pulse width of each pulse is constant.
The signal thus divided into pulses is radiated as a radio wave to a target object (not shown) via the transmission antenna 7, and the signal reflected by the target object is received by the reception antenna 8.
The signal received by the receiving antenna 8 is mixed with the continuous wave (that is, the second continuous wave signal) distributed by the distributor 4 by the mixer 6, and a baseband signal is output.
Note that the continuous wave (second continuous wave signal) distributed by the distributor 4 can be interpreted as a reference signal when the received signal is converted into a baseband signal by the mixing action in the mixer 6. The continuous wave (second continuous wave signal) distributed in (1) may also be referred to as a reference wave for conversion.

Note that there is a certain amount of unwanted coupling in the actual circuit.
Considering unnecessary coupling from the transmission switch 5 to the mixer 6, the received signal is input to the mixer 6 as a large reception signal having the same timing as the pulse of the transmission signal.
In order to avoid “saturation in an AD converter (ADC) 9 to be described later” due to this signal, the baseband signal output from the mixer 6 is cut off only while the pulse of the transmission signal is output by the reception switch 10. To work. As a result, a signal in which the transmission pulse is superimposed on the reception signal due to unnecessary coupling is removed.

FIG. 3 shows the relationship between the transmission signal and the reception signal.
FIG. 3A shows a transmission signal, and the transmitted pulse is received with a delay by a time required for the round trip of the distance to the target object.
Therefore, the received signal from the target object at a short distance (output of the mixer 6) is as shown in FIG. 3B, and the received signal from the target object at a long distance is as shown in FIG.
Since the reception switch 10 cuts off the signal while the pulse of the transmission signal is being output as described above, the signal output from the reception switch 10 is shown in FIG. 3 (d) and FIG. 3 (e).
As shown in FIG. 3D, a part of the pulse of the reception signal from the target object at a short distance is removed by the reception switch 10 and the pulse width is shortened.
On the other hand, the received signal from the target object at a long distance is not affected by the receiving switch 10 and the pulse width does not change.
From the above, for a short-distance target object in which the time required for the pulse signal to reciprocate with the target object is shorter than the pulse width, the pulse width is shortened and output from the reception switch 10, and other long-distance objects are output. For the target object, the pulse width does not change.

Here, since the pulse width and the bandwidth of the receiver that provides the optimum signal-to-noise ratio are inversely proportional (see, for example, the description of p185 in Non-Patent Document 1), the pulse width varies depending on the distance to the target object as described above. A low-pass filter (LPF) having a different bandwidth is used for a signal having.
Specifically, the low-pass filter 1 (LPF1) 11 sets the bandwidth optimized for the pulse width transmitted for long-distance measurement.
On the other hand, the low-pass filter 2 (LPF2) 12 is set to have a wider bandwidth than the low-pass filter (LPF1) 11 for short distance measurement.

In the present embodiment, the bandwidth of the low-pass filter 2 (LPF2) 12 is set to twice the bandwidth of the low-pass filter 1 (LPF1) 11.
The two types of low-pass filters (LPFs) set in this way are switched as shown in FIG.
FIG. 4A shows a transmission signal. Since the pulse width of the received signal is shortened by the receiving switch 10 as described above until the time twice as long as the pulse width Tpw has elapsed since the transmission signal was turned on, the low-pass signal having a wide bandwidth is used. A filter 2 (LPF2) 12 is used.
Thereafter, the low-pass filter 1 (LPF1) 11 is used.
That is, the filter changeover switch 13 is controlled as shown in FIG.

The baseband signal that has passed through the appropriate low-pass filter (LPF) according to the distance to the target object in this way is sent to the AD converter 9 at a timing as shown in FIG. It is sampled at.
The AD converter 9 performs AD conversion at the rising edge of the signal in FIG. That is, sampling is performed at predetermined intervals with reference to the pulse transmission time.
Here, each sampling time is called a range gate, and numbers RG1, RG2,.
The distance R between the target object and the delay time Td between the transmission signal and the reception signal has a proportional relationship expressed by the following equation (2). Therefore, the target depends on which range gate the signal is received at. You can see the approximate distance to the object. In equation (2), c is the speed of light.
In the present embodiment, the low-pass filter 2 (LPF2) 12 having a wide bandwidth is used only for the range gate RG1, and the low-pass filter 1 (LPF1) 11 having a narrow bandwidth is used for the other range gates. It will be.

Such sampling is performed for each pulse transmission during one period of frequency modulation as shown in FIG.
As described above, the reception data sampled by the AD converter 9 is input to the CPU 1 and the distance and relative speed with the target object are calculated.
First, in the frequency modulation shown in FIG. 2, a period in which the frequency increases with the passage of time (UP phase) is distinguished from a period in which the frequency decreases (DOWN phase). Data is collected for each range gate.
Next, the received data collected for each phase and each range gate is frequency-converted to obtain a spectrum waveform for each phase and each range gate.

Peak detection processing is performed on each spectrum waveform using a predetermined threshold value to obtain each frequency (beat frequency).
Here, a peak appears in the spectrum of the range gate corresponding to the distance where the target object exists.
Here, it is assumed that beat frequencies of “RGk (k = 1, 2,...)” In each phase of UP and DOWN are fuk and fud, respectively.
At this time, similarly to a general FMCW (Frequency Modulation Continuous Wave) radar, in the range gate where the peak is detected, the distance Rk to the target object and the relative velocity Vk according to the following equations (3) and (4). Is calculated.

Here, c is the speed of light, Tm is the modulation time, Fm is the frequency modulation width, and λc is the wavelength of the carrier wave.
The relative speed Vk is positive on the side where the target object approaches.
If the distance Rk to the target object calculated by Equation (3) contradicts the distance corresponding to RGk, it is determined as false detection and the calculation result is rejected.
In the present embodiment, two types of low-pass filters (LPF) having different bandwidths are provided, and the band of the low-pass filter (LPF) through which the baseband signal passes by switching them with the filter changeover switch 13 is used. However, it is needless to say that the same effect can be obtained even if it is controlled using a low-pass filter (LPF) whose bandwidth is variable.
In this embodiment, the reception switch 10 is used to remove the transmission pulse superimposed on the reception signal due to unnecessary coupling. However, an amplifier having a variable gain or an attenuator having a variable attenuation is used. Even if the gain is reduced or the attenuation is increased while the transmission signal is being output, the same effect can be obtained.

According to the first embodiment, since the signal due to unnecessary coupling of transmission pulses is removed by the reception switch 10, it is not necessary to increase the dynamic range of the AD converter 9, and the cost can be reduced.
In addition, since a filter with a wide bandwidth is used for a received signal from a short-distance target object whose pulse width has been shortened by the receiving switch 10, measurement is also performed with a good SN ratio even for a short-distance target object. Can do.
Furthermore, since both the short-distance target object and the long-distance target object are measured with one type of pulse width without changing the transmission pulse width, the measurement can be performed in a short time.

In addition, the pulse radar device according to the present embodiment applies frequency modulation in which the frequency change amount per unit time is substantially constant with respect to the first continuous wave signal output from the oscillation means (voltage controlled oscillator 3). Modulation signal generation means (modulation signal generator 2) for generating a modulation signal is provided.
Since the distance and relative speed detection using the beat frequency is performed by performing frequency modulation, the distance to the target object can be accurately measured.
Furthermore, since the erroneous detection is rejected by comparing the distance calculation result using the beat frequency with the approximate distance based on the sampling timing of the received pulse, the reliability of the distance measurement result with the target object can be improved.

  As described above, the pulse radar device according to the present embodiment oscillates the first continuous wave signal in the radio frequency band and outputs the first continuous wave signal, and the first output from the oscillation means. A second continuous wave signal generating means (for example, a distributor 4) that generates a second continuous wave signal that is phase-synchronized with the continuous wave signal, and a pulse obtained by dividing the first continuous wave signal output from the oscillating means into pulses. Pulse modulation means (transmission switch 5 and CPU 1) for generating a wave, transmission means (transmission antenna 7) for transmitting the pulse wave output from the pulse modulation means toward the target object, and receiving the pulse wave reflected by the target object Receiving means (receiving antenna 8), and a mixing means (mixer 6) for mixing the reception signal received by the receiving means and the continuous wave signal generated by the second continuous wave signal generating means to output a mixed signal , Pa It is composed of reception switch means (reception switch 10 and CPU 1) that prevents the mixed signal from being output from the mixing means while the S-wave is being transmitted, and a plurality of low-pass filters (LPF) having different pass bandwidths, Filter means (low-pass filter 1 (LPF1) 11 and low-pass filter 2 (LPF2) 12) for shaping the output signal from the receiving switch means and pulse modulation means divide the first continuous wave signal into pulses. Sampling means (ADC 9 and CPU 1) for sampling the output signal from the filter means at a predetermined sampling interval with the time as the reference time, and a plurality of low-pass filters (filtering means) according to the elapsed time from the reference time ( Filter control means (filter cutting) that changes the pass bandwidth of the filter means by switching the LPF) Has an example switch 13 and CPU1).

Therefore, according to the present embodiment, it is possible to measure the distance to both the short-distance and long-distance target objects in a short time and with a good S / N ratio by one-time pulse transmission.
Moreover, even if there is unnecessary coupling in the circuit, it is not necessary to increase the dynamic range of the AD converter, so that the cost of the device can be reduced.
In the above description, the case where the distributor 4 is used as the second continuous wave signal generating means is shown. However, the present invention is not limited to this. For example, the second continuous wave signal in phase with the first continuous wave signal is used. A phase-locked oscillator that generates the continuous wave signal may be provided separately.

Embodiment 2. FIG.
FIG. 5 is a diagram showing a configuration of the pulse radar apparatus according to the second embodiment.
The process is the same as in the first embodiment until a frequency-modulated continuous wave is output from a VCO (voltage controlled oscillator) 3 based on an instruction from the CPU 1, and a description thereof will be omitted.
The continuous wave (first continuous wave) output from the VCO (voltage controlled oscillator) 3 is input to the transmission / reception changeover switch 14.
FIG. 6 is a diagram illustrating the relationship between transmission pulses, filter switching, and sampling timing in the second embodiment, and FIG. 6A illustrates the operation of the transmission / reception switching switch 14 instructed by the CPU 1.

As shown in FIG. 6A, the transmission / reception changeover switch 14 is connected to the transmission side, that is, the transmission antenna 7 side during the transmission pulse width Tpw, and is connected to the reception side, that is, the mixer 6 side otherwise.
As a result, the transmission antenna 7 is supplied with a signal having a pulse width Tpw.
Needless to say, since the transmission / reception changeover switch 14 switches the input signal between the transmission side and the reception side and outputs it, the output signal is in phase with the input signal, and the baseband signal is output by mixing in the mixer 6. It becomes possible to do.
The frequency modulation in the VCO (voltage controlled oscillator) 3 and the transmission pulse generation in the transmission / reception changeover switch 14 are as shown in FIG.

In this way, a signal in which the first continuous wave output from the VCO (voltage controlled oscillator) 3 is divided into pulses is radiated as a radio wave to a target object (not shown) via the transmission antenna 7 and reflected by the target object. The received signal is received by the receiving antenna 8.
The signal received by the receiving antenna 8 is mixed with the signal supplied from the transmission / reception changeover switch 14 by the mixer 6 to output a baseband signal.
At this time, power is not supplied to the mixer 6 by the transmission / reception changeover switch 14 while the transmission pulse is on, so that no baseband signal is output from the mixer 6.
Therefore, even if unnecessary coupling from the transmission / reception changeover switch 14 to the mixer 6 occurs, a baseband signal due to this unnecessary coupling is not output, and “saturation in the AD converter 9 described later” can be avoided.
Similarly to the first embodiment described above, for a short-distance target object in which the time required for the pulse signal to reciprocate with the target object is shorter than the pulse width, the pulse width is shortened and output from the mixer 6. The pulse width does not change for other long-distance target objects.

The baseband signal output from the mixer 6 is switched as shown in FIG. 6B by the filter changeover switch 13 as in the first embodiment, and the received signals from the target objects at the short distance and the long distance are respectively received. It operates so that measurement is performed with a good S / N ratio.
As in the first embodiment, the low-pass filter 1 (LPF1) 11 is set to a bandwidth optimized for the pulse width transmitted for long-distance measurement, and the low-pass filter 2 (LPF2) 12 is set to a bandwidth twice that of the low-pass filter 1 (LPF1) 11 for short distance measurement.
In the AD converter 9, sampling is performed at the timing shown in FIG. 6C, and the distance and relative speed from the target object are calculated in exactly the same manner as in the first embodiment.

  As described above, the pulse radar device according to the present embodiment has the oscillation means (voltage controlled oscillator 3) for oscillating and outputting the first continuous wave signal in the radio frequency band, and the continuous wave signal output from the oscillation means. To generate a first pulse wave by connecting to the transmitting side while the pulse width of the generated pulse wave is a predetermined pulse width, and the pulse width of the generated pulse wave is When the pulse width is other than the predetermined pulse width, the transmission / reception switching unit (transmission / reception switching switch 14) generates the second pulse wave by switching to the reception side, and the first pulse wave output from the transmission / reception switching unit is directed toward the target object. Transmitting means for transmitting (transmitting antenna 7), receiving means for receiving the first pulse wave reflected by the target object (receiving antenna 8), received signal received by the receiving means and transmission / reception switching means It is composed of mixing means (mixer 6) for mixing the second pulse wave to be output and outputting a mixed signal, and a plurality of low-pass filters (LPFs) having different pass bandwidths. The output signal from the receiving switch means Filter means (low-pass filter 1 (LPF1) 11 and low-pass filter 2 (LPF2) 12) to be molded and the time from the transmission / reception switching means connected to the transmission side as a reference time from the filter means at a predetermined sampling interval Sampling means (CPU 1 and ADC 9) for sampling the output signal and a plurality of low-pass filters (LPF) constituting the filter means are switched according to the elapsed time from the reference time, and the pass bandwidth of the filter means is changed. Filter control means (filter changeover switch 13 + CPU1) is provided.

  Therefore, according to the present embodiment, the switch (transmission switch 5) that generates the transmission pulse and the switch (reception switch 10) that eliminates the superposed signal due to unnecessary coupling in the first embodiment are combined into one transmission / reception switching switch 14. Since they can be consolidated, the effects of the first embodiment described above can be obtained, and the cost of the apparatus can be further reduced.

  INDUSTRIAL APPLICABILITY The present invention is useful for realizing a low-cost pulse radar apparatus that can measure the distance to a target object at a short distance and a long distance with a good SN ratio and does not need to increase the dynamic range of the AD converter.

1 CPU
2 Modulation signal generator 3 VCO (voltage controlled oscillator)
4 distributor 5 transmission switch 6 mixer 7 transmission antenna 8 reception antenna 9 AD converter 10 reception switch 11, 12 low-pass filter (LPF)
13 Filter selector switch 14 Transmission / reception selector switch

Claims (4)

Oscillating means for oscillating and outputting a first continuous wave signal in a radio frequency band;
Second continuous wave signal generating means for generating a second continuous wave signal that is phase-synchronized with the first continuous wave signal output by the oscillating means;
Pulse modulating means for dividing the first continuous wave signal output from the oscillating means into a pulse wave by dividing it into pulses, and
Transmitting means for transmitting the pulse wave output from the pulse modulating means toward a target object;
Receiving means for receiving the pulse wave reflected by the target object;
Mixing means for mixing the reception signal received by the receiving means and the continuous wave signal generated by the second continuous wave signal generating means to output a mixed signal;
Receiving switch means for preventing the mixed signal from being output from the mixing means while the pulse wave is being transmitted;
Filter means for shaping an output signal from the reception switch means;
Sampling means for sampling the output signal from the filter means at a predetermined sampling interval with a time at which the first continuous wave signal is divided into pulses in the pulse modulation means as a reference time;
A pulse radar apparatus comprising filter control means for changing a pass bandwidth of the filter means according to an elapsed time from the reference time.   The second continuous wave signal generating means distributes the first continuous wave signal output from the oscillating means to generate a second continuous wave signal that is phase-synchronized with the first continuous wave signal. The pulse radar device according to claim 1, which is means. Oscillating means for oscillating and outputting a first continuous wave signal in a radio frequency band;
The continuous wave signal output from the oscillation means is divided into pulses to generate a pulse wave, and the first pulse wave is generated by connecting to the transmission side while the generated pulse wave has a predetermined pulse width. A transmission / reception switching means for generating a second pulse wave by switching to the reception side when the pulse width of the generated pulse wave is other than the predetermined pulse width;
Transmitting means for transmitting the first pulse wave output from the transmission / reception switching means toward a target object;
Receiving means for receiving the first pulse wave reflected by the target object;
Mixing means for mixing the received signal received by the receiving means and the second pulse wave output from the transmission / reception switching means to output a mixed signal;
Filter means for shaping an output signal from the reception switch means;
Sampling means for sampling the output signal from the filter means at a predetermined sampling interval with reference to the time when the transmission / reception switching means is connected to the transmission side;
A pulse radar apparatus comprising filter control means for changing a pass bandwidth of the filter means according to an elapsed time from the reference time.   Modulation signal generating means for generating a modulation signal for performing frequency modulation in which the frequency change amount per unit time is substantially constant with respect to the first continuous wave signal output from the oscillating means is provided. The pulse radar device according to any one of claims 1 to 3.

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